But the truth is corporate America is tiring of the suburbs and returning to downtown like so many empty nesters—or hipsters, since many companies cite attracting top young talent as a factor in their decision to set up shop downtown. In Seattle, Microsoft and Expedia are on the move. In Atlanta it’s AT&T, and Target in Minneapolis. Meanwhile, Quicken Loans has just moved 1,700 employees into downtown Detroit. Yes, Detroit... (Blue Cross Blue Shield is scheduled to add 3,000 more in 2011.)

Some of these companies are moving into old buildings—Adidas’ and Amazon’s new HQs, for instance, are both housed in old hospitals. Others are building new HQs on reclaimed brownfields. American Eagle’s new Pittsburgh offices are where a steel mill once stood, while Pixar’s new digs went up on the site of an old Del Monte cannery. “What we really wanted was to find a big, old brick building and rehabilitate it, but we couldn’t, so we built it instead,” said then CEO Steve Jobs.

That second paragraph demonstrates the pull of Rust Belt Chic and the importance college degree density in terms of job location. Talent reverse commuting to suburban office parks ringing the city makes the residential density gains moot. Why should we care where the brains live?

That's something that regions with relatively low educational attainment rates should ponder. If talent is scarce, then you best concentrate jobs. That's easier to do in Rust Belt cities where prime real estate is cheap. The so-called "creative economy" favors these regions that talent is supposed to be fleeing.